Question for the Gear Ratio Guru's

[lowracer]

I'm getting ready to put my 2nd MB together & have a gear ratio question.
What diameter drive pulley would I need to use?
I'm spot welding a narrow rim to my mountain bike rear wheel to run a v-belt. The actual diameter is 22" (not 26").
I'd like to get about 40 mph using a 2hp, 2 stroke, 40cc without other transmission reduction bolt-ons.
Thanks
-Alex-

 

[levsmith]

we need to know the rpm of the motor

 

[lowracer]

Oopsy...
Peak horsepower is 2hp @ 6000 rpm.
Peak torque is ? @ 5000 rpm.